Build a Bluetooth‑Controlled Raspberry Pi Robot with Audio Feedback

In this guide we’ll extend the classic Raspberry Pi robot project by adding Bluetooth control and dynamic sound effects. We’ll connect an Arduino Uno to a Bluetooth module, relay commands to a Raspberry Pi, and use Python to play .wav files that correspond to each command. The result is a robot that moves and “talks” in real time.

Step 1: Parts & Hardware

• Raspberry Pi (any model with USB ports, Pi 3 or newer recommended)
• Arduino Uno
• Motor driver (e.g., L298N) and wheels/axles
• 9‑V battery or Li‑Po pack (for the robot base)
• Bluetooth serial module (Silversilvermate or HC‑05)
• Powered speaker with 3.5 mm jack
• Connecting wires, resistors, and a breadboard (if needed)
• Optional: case or chassis for the robot

All core components are covered in the original robot build guide. The Bluetooth module can be purchased from Zagros Robotics.

Step 2: Prepare the Raspberry Pi

Use the latest NOOBS image (v1.2.1 or newer) to avoid audio‑jack issues that plagued older Raspbian releases. Once the Pi is booted:

1. Open a terminal and confirm Python 2.7 (or 3.x if you prefer).
   python --version
2. If you need a specific version, install it via sudo apt-get install python2.6 (though Python 2.7 is fully supported).
3. Install the serial library required for communication with the Arduino:
   sudo apt-get install python-serial
4. Enable the 3.5 mm audio jack: amixer cset numid=3 1
5. Create a /home/pi/Sounds folder and download the following WAV files:
   • forward.wav
   • backward.wav
   • left.wav
   • right.wav
   • stop.wav
6. Download the Python script zagbot-bt.py into /home/pi and make it executable: sudo chmod +x /home/pi/zagbot-bt.py

Step 3: Arduino & Bluetooth Wiring

Connect the Bluetooth module to the Arduino using SoftwareSerial on pins 2 (TX) and 3 (RX). The wiring diagram is as follows:

• Arduino TX (pin 2) → Bluetooth RX
• Arduino RX (pin 3) → Bluetooth TX
• Arduino 5V → Bluetooth VCC
• Arduino GND → Bluetooth GND
• Bluetooth CTS → Arduino RTS (optional, for flow control)

Upload the zagbotbt.ino sketch to the Uno. This sketch forwards any string received over Bluetooth to the USB serial port connected to the Raspberry Pi.

Step 4: Android Control App

Download the sample Android APK Max_Control from Box. Transfer it to your device’s SD card, then install using an app like ES File Explorer (tutorial). The app sends simple text commands (e.g., "FORWARD", "BACKWARD") over Bluetooth to the Arduino.

Step 5: Run the System

1. Power the robot base and ensure the Arduino is connected to the Pi via USB.
2. Start the Python listener on the Pi:
   python /home/pi/zagbot-bt.py
3. Launch the Android app and pair with the Bluetooth module.
4. Press a movement button and hear the corresponding sound play on the Pi speaker.

Congratulations – you now have a fully functional, Bluetooth‑controlled Raspberry Pi robot that reacts audibly to each command. Feel free to expand the project: add more sound files, integrate an accelerometer for gesture control, or switch to Python 3 for future‑proofing.